FROM TANGANYIKA AND KENYA 145 



of a locality along the Central Railway, Tanganyika, and appears to have a more 

 prominent apex than the form now recorded. The shell from the Saurian Beds 

 of Tendaguru recorded by Dietrich (1914 : 126, pi. n , figs. 10a, b) as Nerita cf. 

 transversa v. Seebach var. minor de Loriol differs from the specimens now recorded 

 in much the same manner as does N. louisiae. 



Genus LISSOCHILUS Zittel 1882 



Lissochilus stremmei Dietrich 

 PI. 24, figs. 4a, b 



1914. Nerita (Lissochilus) Stremmei Dietrich : 126, pi. n, figs. na-e. 



Material. Three specimens (nos. G. 48903, G. 48912, GG.10315). 



Localities and horizons. Kipande, W. of Tendaguru, Tanganyika ; Upper 

 Kimmeridgian, Nerinea Beds. Kindope valley, N.W. of Tendaguru ; Upper 

 Kimmeridgian, " Trigonia smeei " Beds. i\ miles N.W. of Mandawa, Tanganyika ; 

 Upper Kimmeridgian. 



Remarks. In this species a strong rounded carina forms the periphery of the shell 

 and a strong, rounded-off angulation marks the boundary of a subhorizontal sutural 

 shelf. Below the periphery are several spiral cords, one of which may stand out as a 

 keel. Rather irregularly distributed collabral ridges are most conspicuous on the 

 later formed part of the last whorl and give rise to tubercles on some of the spirals. 

 The two largest specimens now recorded, which are rather eroded, are about 23 mm. 

 in diameter. 



Superfamily PALAEOTROCHACEA 



Family PARATURBINIDAE Cossmann 1916 



Genus CHARTRONELLA Cossmann 1902 



Chartronella mitoleensis sp. nov. 

 PL 24, figs. 3a, b 



Diagnosis. Shell of medium size, trochiform, with height (19 mm. in the holo- 

 type) very slightly exceeding diameter. Whorls bicarinate, the upper carina 

 forming the edge of a subhorizontal, slightly concave sutural ledge, the lower, which 

 projects abaxially slightly more than the upper one, just exposed above the suture 

 on the later whorls and forming the periphery of the base of the shell. Outer face 

 of whorls, between the carinae, concave. Base convex, umbilicus absent. Narrow 

 spiral cords, with transverse threads crossing their intervals, are present near the 

 carinae, but spiral ornament is absent from the remainder of the shell (it could 

 conceivably, however, have been removed by erosion in the holotype). Aperture 

 almost circular (the outer lip is broken in the holotype) ; a spiral swelling originating 

 at the lower margin of the aperture forms the lower border of the convex part of the 

 base. 



